A new generation of confocal microscopes, capable of UV and visible excitation and video-rate imaging, will be developed in Phase II. Prototype versions of both upright and inverted microscope configurations will be constructed using the concepts for chromatic corrections and video-rate scanning that we established during Phase I. These prototype confocal microscopes will incorporate unique optical and mechanical designs that will permit the use of a relatively simple and efficient, new optical layout that will fit on current commercial upright microscopes. The unique capabilities of this new design will provide researchers with the most flexible control of such experimental parameters as choice of laser illumination sources, fluorescent dyes, resolution, detection limits, and scan rates. The new microscopes will greatly expand the number of applications of UV through red excited fluorescent dyes, simultaneous multiple wavelength excitation and detection, and the use of caged compounds. PROPOSED COMMERCIAL APPLICATION: The availability of a video-rate confocal microscope that is capable of both UV and visible excitation would greatly broaden the number of applications for confocal fluorescence microscopy. These new applications, such as quantitative calcium measurements in live cells in situ, would provide compelling reasons for neurobiologists to purchase our confocal microscope.